Converting device for steam-engines



4 Sheets-Sheet 1.

(No Model.)

P. W. LEPPLER. CONVERTING DEVICE FOR STEAM ENGINES.

Patented Mar. 31, 1891.

t l I lt (No Model.) 4 Sheets-Sheet 2.

P. W. LEFFLER. CONVERTING DEVICE EOE STEAM ENGINES. No. 449,162. Patented Mar. 31, 1891.

(No Model.) 4 Sheets-Sheet 3. P. W. LEPFLER. CONVERTING DEVICE FOR STEAM ENGINES.

Patented Mar. 31,1891.

we nonms 9:15 :0, mord'umm, maximum 11. c.

(No Model.) 4 Sheets-Sheet 4.

P. WQLEFPLER. CONVERTING DEVICE FOR STEAM ENGINES. No. 449,162. Patented Mar. 31,1891.

Ziy-$' W Wifiwswfi v I a. yaw, i

114i mam: vex-ens cm, mmo-mnm, wnsmxm'gu, n. c.

' UNITED STATES PATENT EEIcE.

PAUL IV. LEFFLER, OF MINNEAPOLIS, MINNESOTA.

CONVERTING DEVICE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 449,162, dated March 31, 189 1. Application filed March 10 1890. Serial No. 348,224. (No model.)

T0 at whom, it may concern:

Be it known that I, PAUL IV. LEFFLER, a citizen of the United States, residing at Minneapolis, in the county of I-Iennepin and State of Minnesota, have invented certain new and useful Improvements in Converting Devices for Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Myinvention relates to reciprocating steam engines, and has for its object to economize steam by providing a peculiar converting device for imparting the motion of the pistons to the power-shaft, which will permit the use of the steam expansively down to the full end of the stroke.

In myinvention, which is shown as applied to a compound engine of the Corliss type, an elongated endless rack is provided with a stem pivoted to the cross-head of each pistonrod, the teeth of the rack belng 1n engagement with a pinion on the shaft to which the power from the engine is applied.

In order to strengthen the construction and to insure steadiness of motion, each rack is provided with a plain continuous rib or flange on either side at the pitch-line of the teeth, and the pinion with which the rack engages is also formed with plain circular portions which roll upon a similar portion of the rack. The racks attached to the cross-heads of the high-pressure and low-pressure cylinders are so arranged with respect to each other that when one rack is at the end of its stroke in one direction the other rack is at the end of its stroke in the opposite direction. Attached to the respective ends of the shaft to which the power is applied are the usual pulley and the fly-wheel by which the power is stored up. A continuous guide or track, bordered on one side by a flange, is formed on the external surface of each rack. Mounted loosely on the power-shaft between the two pinions with which the racks engage is a sleeve having arms projecting at right angles therefrom, and each provided with awrist-pm on which an anti-friction roller in engagement with the track or guide is journaled. When the racks arrive simultaneously at the ends of their respective strokes, the momentum of the shaft to which the power is applied will cause the pinions thereon to engage the teeth upon the curved inner ends of the racks, thereby throwing the end of one rack upward and the other downward and forcing the guide or track of each rack against the rollers on the wrist-pins with su fficient friction to cause the sleeve and its rollers to make a half revolution. By means of these rollers the racks are held in constant engagement with the pinions, and as the end of each rack is pivoted to the crosshead connected to the piston-rod of each cylinder, it is thus enabled to have imparted to it the vertical motion necessary to accomplish the result just described.

Attached to the cross-head of each engine is an arm on which a suitable spring is placed for sustaining the weight of the rack.

As before stated, the compound engine shown is of the Corliss type, provided with the usual governor and valve-operating gear, and with the high and low pressure cylinders.

In the accompanying drawings, in which like symbols of referencecare placed on like parts throughout the several views,.Figure l is a side elevation of a Corliss engine, showing my invention applied thereto. Fig.2 is a plan view, with the cylinders and a portion of the framework in section. Fig. 3 is a side view, with parts broken away and with an end of one of the racks and one of the pinions shown in section; and Fig. at is a detailed view,witl1 the racks and pinions in sections.

A is a reciprocating steam-engine of the Corliss type.

B and B are respectively the high and low pressure cylinders thereof, in which the usual pistons C C play baokand forth.

D D. are reciprocating cross-heads to which the piston-rods are connected.

E is the valve-gear, F the governor, and F the rods connecting it with valves, and G the steam-delivery pipe to the high-pressure cylinder. u

ll is the hook-rod [or actuating the valvegear, and I1 is the lever to which it is connected.

The devices thus far described are those usually found in the class of engines to which attention has been directed, and they constitute no part of my invention.

I is a shaft journaled in bearings upon one end of the frame-work of the engine, said shaft being provided with the usual fly-wheel and pulley.

J J are pinions rigidly secured to shaft I at points respectively opposite the high and low pressure cylinders, each pinion being provided with a plain circularrib or flange j, extending to the pitch-line of the teeth.

K K are elongated endless racks, the internal teeth of which are in engagement with the pinions J J. Each rack is formed on either side of its internal teeth with a continuous plain portion or rib 7t 7;. k, which is supported by and moves upon the smooth circular ribsjjj'j of the pinions J J. On its top surface each rack is formed as a continuous track 7. bordered on one side by a vertical flange Projecting from the forward end of each rack is a stem 70*, pivoted at k to its cross-head D or D.

L L are brackets, one projecting from each cross-head, and Z Z are springs for sustaining the weight of the racks mounted on said brackets. t

M is a sleeve loosely mounted on shaft I between the pinions J J, and provided with projecting arms at m, each carrying a wristpin, on which an anti-friction roller m m is placed. The purpose of these ribs 7c 70 7s 76' is to prevent lateral displacement of the pinion and by co-action with the wrist-pin M and anti-friction rollerM, together with the track 70 to secure uniform engagement between th pinion' and the rack. The wrist-pins, with their rollers, shift from above to below the rack at the ends of the strokes in virtue of the momentum on the pinion and the resultant of forces, as described, and thus the pinion is made to engage with the upper rack while the piston is moving in one direction and with the lower rack while the piston is moving in the other direction, thus imparting a uniform or continuous motion in the same direction to the pinion.

For driving the valves it is impossible with this form of converting device for applying the power from the piston to use the ordinary eccentric or any equivalent device on the power-shaft, inasmuch as the power-shaft will revolve several times for every stroke of the piston. Hence a reducing-gear of some kind must be interposed between the powershaft and the valvegear proper. To this end I place a small pinion N on the powershaft I and make the same engage with a large wheel 0, journaled on the main frame, which is provided with a crank-pin connected by a pitman Q with the yalve-driviug rockerarm 11. In this manner the valve movements may be timed, as required.

The peculiar converting device herein described is especially adapted to compound engines, inasmuch as the opposite wrist-pins and their rollers M M on the common sleeve M counterbalance each other. It is, however, capable of application to single-cylinder engines but in that case a counter-weight would have to be employed to balance the wrist-pin and its roller.

I have described the parts K K as elon gated endless racks; but they might equally well be regarded as elongated internal gears.

I-Iaving fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination, with a reciprocating engine, of an elongated endless rack secured to the engine-piston, a pinion on the power shaft engageable with the rack, and a pivoted guide loosely mounted on the power-shaft adjacent to the pinion, adapted to hold the pinion in engagement with the rack and shaft, the rack to ettect continuous motion of the pinion in the same direction.

2. The combination, with a reciprocating engine, of an elongated endless rack pivotally connected to the piston, a pinion on the power-shaft engageable therewith, and a pivoted guide on the power-shaft for holding the pinion and rack in engagement and shifting the rack to engage the opposite sides of the pinion at the ends of the stroke, substantially as and for the purpose set forth.

8. The combination, with a reciprocating engine, of an elongated endless rack secured to the piston and provided with a guideway or track, a pinion on the power-shaft, and a pivoted guide loosely mounted on said powershaft and provided with a head movable over said track, substantially as and for the purpose set forth.

et. The combination, with an engine-piston, of an elongated endless internally-toothed rack provided with a guide-track on its exterior surface and projecting ribs or shoulders on its interior edges, a pinion on the power-shaft having shoulders or ribs engageable with the rack, and a pivoted guide loosely mounted on said shaft, having a projecting head movable on said track, substantially as described.

5. The combination, with a reciprocating engine, of an elongated endless rack secured to the piston and provided with a guideway or track,a pinion on the power-shaft, and a pivoted guide loosely mounted on said shaft, having an anti-friction roller movable on said track, substantially as described.

6. The combination, with a compound ongine, of a pair of elongated endless racks pivotally connected respectively one to each piston, and provided with a guidcway or track,

IIO

a pair of pinions spaced apart on the power- In testimony whereof Iaffix my signature in lo shaft engageable one with each of said racks, presence of two witnesses.

and a sleeve loosely mounted on said shaft a between said pinions, having crank-arms set PAUL W. LEFFLER. opposite to each other, provided with a projecting head movable one in each of said Witnesses:

guideways for effecting the proper engage- WM. H. BLODGETT,

ment of the racks with the pinions, substan- A. H. OPSAHL.

tially as described. 

